The goal of this project is to develop innovative lossless regions-of-interest (ROI) watermarking techniques to make the usage, archiving, and communication of medical images much more secure and manageable. Currently available techniques only provide means of ubiquitous watermarking that are inapplicable to most medical images. The proposed technology offers an effective means of data authentication, security, and copyright protection by embedding imperceptible watermarks into the images without modifying the content of the ROI. These watermarks remain present after copying, internet transmission, or even some alteration, and can be retrieved when needed. Important information such as specimen identification, laboratory signature and specification can be encoded into the watermarks. This functionality will enable clinicians and researchers to effectively protect the authenticity and integrity of their digital image data. In Phase 1 we will study the feasibility of lossless ROI watermarking on simple modality medical images. We will develop a prototype system to implement the proposed watermarking approach. We will develop an image segmentation method that processes and keeps track of the partition and location of the image regions based on the ROI delineation. In conjunction with the region segmentation, we will implement both a spatial-domain and a wavelet-domain watermarking schemes with the improvement to enable selective watermarking into non-ROI parts of the images, and to test them using single-frame monochrome medical images. We will evaluate these schemes in terms of watermark (1) imperceptibility, (2) capacity, and (3) robustness. If the proposed technique proves to be viable, in Phase 2 the technology will be extended to and tested on complex modality medical images. When fully developed, we will patent the new technology and commercialize it through licensing agreements and partnerships with manufacturers of medical imaging systems and companies of general image processing and publishing software products.